Migrate Modules to dir. Modules

As already described in #33 there is a new directory for future modules.

Please move current modules like send_mail.py etc. to this dir and make sure they still work fine. References to existing directories must be checked. Please use the os.path.join() to make sure the path references work on all OS.

@Skupino could you please check it?

Find the existing modules like send_mail.py in the repository root. Move them to the new modules directory mentioned in issue #33. Update all import statements and file references in other scripts to use os.path.join() for cross-platform compatibility. Test that the moved modules still function correctly by running any existing tests or sample scripts.

索引モデルが issue の本文から書いたものです。